Microwave connector



June 13, 1967 L. R. BARKER 3,325,752

MICROWAVE CONNECTOR Filed Febv l, 1965 2 Sheets-Sheet l 26 5727 FIG: 2

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INVENTOR. LESTER R. BARKER S ATTORNEYS June 13, 1967 1.. R. BARKER 3,325,752

MI CROWAVE CONNECTOR Filed Feb. 1, 1965 2 Sheets-Sheet 2 J W/V A 2% 3; 322 24'57 m 15s F/G 58 I INVENTOR. LESTER RuBARKER A TTOHNEYS United States Patent ()filice 3,325,752 Patented June 13, 1957 $325,752 MHCRQWAWE CONNECTQR Lester R. Barker, New Brunswick, NJ assignor to Electronics Standards Corp. of America, Plainfield, N.J., a corporation of New Jersey Filed Feb. 1, 1%51 Ser. No. 429,36 8 (Zlaims. ((Il. 333--34) This invention relates to microwave connectors and, more particularly, to a new and improved microwave connector arrangement for joining microwave components having diiferent cross-sectional configurations.

In assembling microwave circuit components, it is often necessary to join a component having a circular crosssectional configuration such as a coaxial cable to a component having a rectangular cross-sectional configuration such as the strip transmission line product referred to as stripline. In conventional connecting arrangements for components of different cross-sectional configuration, however, the arrangements for transforming the microwave signal configuration have an undesirably high voltage standing wave ratio (VSWR) either over an entire frequency range of interest or at particular frequencies within a range of interest so that a broad band, low VSWR transforming connector has not heretofore been available.

Accordingly, it is an object of the present invention to provide a new and improved microwave connector which overcomes the above-mentioned disadvantages of present connectors.

Another object of the invention is to provide a microwave connector capable of joining microwave components of different crosssectional configuration while providing a very low VSWR.

A further object of the invention is to provide a microwave connector especially adapted to connect stripline to coaxial cable.

An additional object of the invention is to provide a microwave connector adapted to connect stripline to cir cuit components such as terminations and the like which have a circular cross-sectional configuration.

These and other objects of the invention are attained by providing a connector which includes an outer conductor member having a circular opening therethrough and which is adapted to be connected at one end of the opening to a component of rectangular cross-sectional configuration and at the other end of the opening to a component of circular cross-sectional configuration, along with a central conductor pin supported in the circular opening and having at the end adjacent to the component of circular cross-section a cross-sectional configuration and at the other end a rectangular cross-sectional configuration. In certain embodiments, the diameter of the circular opening in the outer conductor member is reduced abruptly midway along its length to half the original diameter and, in the same plane, the shape of the central pin abruptly changes from the circular cross-sectional configuration to the rectangular cross-sectional configuration.

Further objects and advantages of the invention will be apparent from a reading of the following description in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view partially broken away illustrating a representative microwave connector arranged according to the invention;

FIG. 2 is a view in longitudinal section taken on the line 22 of FIG. 1 and looking in the direction of the arrows;

FIG. 3 is a view in longitudinal section illustrating another connector arranged according to the invention;

FIGS. 4A, 5A and 6A are views in longitudinal section illustrating further embodiments of the invention;

FIGS. 4B, 5B and 6B are fragmentary plan views showing portions of the connectors illustrated in FIGS. 4A, 5A and 6A, respectively; and

FIG. 4C is a fragmentary plan view showing a modification of the connector illustrated in FIGS. 4A and 4B.

In the representative embodiment of the invention shown in FIGS. 1 and 2, a microwave connector it comprises a metal transformer block 11 having a rectangular exterior configuration and having upper and lower recesses 12 and 13 along one end to receive parallel upper and lower clamping plates 14 and 15, respectively, which are joined to the block 11 by two screws 16. Two further screws 17 clamp the plates 14 and 15 to the opposite sides of a piece of stripline 18 having a rectangular conductor 19 separated by parallel layers of insulative material 20 and 21 from a pair of parallel outer conductors 22 and 23, respectively.

On the other side of the transformer block 11, a tubular metal body 24 is press-fitted into a large diameter bore 25 in the transformer block and a knurled nut 26 is rotatably supported in the body 24 by a spring washer 27 which is retained in an internal groove 28 in the nut 26 and is received in a peripheral groove 29 in the body 24. An internal thread 30 is formed in the nut 26 to connect with a threaded metal member of corresponding size and a resilient Washer 31 made of silicone rubber, for example, is held captive within a recess 32 to engage the end of the mating member. In addition, a tubular contact member 33, made slightly resilient by longitudinal slots 34 so as to assure good contact with the interior surface of a mating member, has a base 35 afiixed to the body 24 which retains two insulating rings 36 and 37 made of electrically pure Teflon between itself and the base of the large diameter bore 25 in the transformer block 11.

In accordance with the invention, the transformer block 11 includes a circular opening 38 extending between the member 24 and the end adjacent to the stripline 18 and, in the embodiment shown in FEGS. 1 and 2, the opening 38 has a large diameter portion 39 at the end adjacent to the :member 24 and an smaller diameter portion 40 at the other end adjacent to the stripline. Centrally supported in the member 24 by the insulative rings 36 and 37 is a pin 41 which extends axially into the tubular contact member 33 and has a tapered projection 42 adapted to be received ina complementary shaped plug connected to the central conductor of a matin component (not shown). To assure accurate longitudinal positioning of the pin 41 and to prevent longitudinal displacement of the pin, as a result of engagement and disengagement of the projection 42, the pin is formed with an annular disk 43 which is positioned in a recess 44 in the insulating ring 37, the thickness of the disk 43 and the depth of the recess 44- being the same. Also, to permit accurate angular positioning of the pin, a knurled section 45 is pressed into the opening of the insulating ring 37.

At its other end, the cylindrical pin 41 terminates abruptly in a perpendicular end surface 46 which lies in the same plane as the abrupt change in diameter of the circular opening 38 from the large diameter 39 to the small diameter 49. inwardly from the end surface 46, the pin is formed with a slot 47 extending in a plane parallel to the recesses 12 and 13 in the transformer block 11 and a fiat metal tab 48 mounted in the slot 47 extends along the axis of the opening 33 through the small diameter portion 40 and into the stripline 18 which is clamped between the plates 14 and 15 to make contact with the center conductor 19 therein. In this way, the microwave signal energy is converted from a circular configuration on the left-hand side of the transformer block 11, as viewed in FIGS. 1 and 2, to a rectangular configuration in the stripline 18 at the right-hand side of the transformer block 11. Preferably, an enlarged recess the opening 38b was 3 49 is provided in the insulative ring 37 on the side facing the central opening 38.

In the operation of a typical connector of the type shown in FIGS. 1 and 2, the VSWR produced by the connector was found to be less than 1.05 at all frequencies from zero to 10,000 megacycles. In that connection, the central opening 38 in the transformer block '11 was /8 inch long and the diameter of the large diameter portion 39 was 0.276 inch while that of the small diameter portion 40 was 0.135 inch, the boundary between those two portions being exactly midway along the length of the opening 38. In addition, the pin 41 had a diameter of 0.120 inch and the tab 48, which extends /2 inch from the end surface 46 of the pin and was tapered along the final 0.150 inch, had a thickness of 0.003 inch and a width of 0.094 inch. Moreover, the recess 49 had a depth of 0.028 inch and a diameter of 0.322 inch. Although the foregoing dimensions for the various components of the connector are not absolutely essential, it has been found that the VSWR performance of the connector may vary considerably from optimum with small changes in the values of or relation between those dimensions.

In the embodiment of the invention shown in FIG. 3, the microwave connector 10a is of the push-on type and is adapted to receive stripline 18a of thinner dimensions than stripline 18 of FIGS. 1 and 2. In this regard, the transformer block 11a of FIG. 3 has recesses 12a and 13a of greater depth and the clamp plates 14a and 150 are of greater thickness than the corresponding components of FIGS. 1 and 2. Also, the tubular body 2411 of FIG. 3 has no provision for receiving a knurled nut or resilient washer but a push-on contact receptacle 50 has a base 51 mounted in the body 24a to retain the insulative rings 36 and 37 therein. In addition, the central pin 41a of the FIG. 3 embodiment has no projection but, insetad, has an internal bore and slots 52 so as to perform a plug to receive the projection 53 of a pin 54 in a mating push-on component 55. The push-on component 55 shown in FIG. 3 is of the type described -in detail in the copending Barker United States application for Microwave Push-On Connector, Ser. No. 429,418 filed Feb. 1, 1965, and includes a resilient tubular contact member 56 received within the receptacle 50 and a resilient isolation ring 57 engaging the outer surface of the receptacle 50. Inasmuch as the interior arrangement and dimensions of the transformer block 11a, as well as those of the pin 41a and the metal tab 48 mounted therein, are the same as those of FIGS. 1 and 2, a detailed description with respect to FIG. 3 is not necessary, the corresponding components being designated with the same reference numerals.

The embodiment of the invention illustrated in FIGS. 4A and 4B differs from that of FIGS. 1 and 2 only in the structure of the transformer block 11b, the clamp plates 14b and b, the central pin 41b and the tab 48b, and in the thickness of the stripline 1817 which is similar to that of FIG. 3. Accordingly, the other elements of the connector which are designated by the same reference numerals as in FIGS. 1 and 2 will not be described in detail with reference to FIGS. 4A and 4B.

In the connector of FIGS. 4A and 4B, the transformer block 1112 is provided with a central circular opening 38b which has a constant diameter bore 39b along its entire length. The central pin 41b, moreover, terminates in a conical tip 46b which is slotted to receive a short tab 48b, the tab projecting out of the opening 38b to engage the center conductor of the stripline 18b. A typical connector made in accordance with the arrangement shown in FIGS. 4A and 4B and providing optimum VSWR performance included a transformer block 11b wherein inch long and the bore 3% had a diameter of 0.265 inch. Also, the tapered tip 46b of the central pin had a length of inch and ended of an inch from the end of the opening 38b. The tab 4817 which was 0.003 inch thick extended 0.212 inch beyond the end of the pin and had a width of 0.190 inch.

The modified form shown in FIG. 4C is the same as that illustrated in FIGS. 4A and 4B except that the short tab 48b is reduced in width along the line of entry into the center of the stripline 185. With this arrangement, exceptionally low VSWR performance is maintained with varying stripline widths and varying circuit board materials and sizes. This provides a universal connector for board application with low VSWR performance. In a preferred form, the tab 48b is reduced in width from 0.190 inch to 0.045 inch at the plane of the end of the central opening 38b.

According to a further embodiment of the invention shown in FIGS. 5A and 5B, the transformer block 110 has a smaller central opening than 380 formed by a bore 39c having a constant diameter of 0.145 inch. In this case, the central pin 41c has a diameter of 0.082 inch and the tab 480 extends inch beyond the end surface 46 of the pin which is located halfway alongthe length of the opening 38c. Furthermore, as best seen in FIG. 5B, the tab 480 which is also 0.003 inch thick is wider than the diameter of the pin, being 0.094 inch wide in the projecting portion and is tapered down to the diameter of the pin at the portion which is received in the pin slot. Moreover, in this embodiment, no recess is provided in the end of the insulative ring 37c which faces the opening 38c. Within the knurled nut 260, which is mounted on a smaller diameter body 240, the insulative ring 36c is retained by the end of the tubular contact member 33c but it has a tubular projection 60 which follows the inner surface of the member 33c to assure sufficient insulation between the pin projection and the contact portion of the member 330.

According to the arrangement shown in FIGS- 6A and 6B, a microwave termination 61 of circular cross-section is connected to a section of stripline 18d by a transformer block 11d provided with recesses 12d and 13d to receive clamp plates 14d and 15d connecting the block of the stripline. The termination 61 is of the type described and claimed in the copending Barker United States application Ser. No. 429,560, filed Feb. 1, 1965, for Microwave Circuit Termination and comprises a tubular metal body 62 mounted in a bore 25d of the block 11d and retainer 63 at the end of the tubular member retaining a metal disk 64 and a sleeve 65 having a tapered internal cavity along with an insulative ring 66 in position within the tubular body 62. Within the cavity of the sleeve 65, a resistor 67 comprising a rod of ceramic material coated with carbon is mounted between a central opening in the disk 64. and a conductive tube 68 which fits over a stud 69 at the end of the central pin 41d.

As in the other embodiments of the invention, the transformer block 11d has a central opening 38d of circular cross-section and, in this case, the opening has a large diameter portion 39 and a small diameter portion the recess 49 are the same as 40, each extending along one-half the length of the opening. The pin 41d, moreover, terminates in an end surface 46 in the plane separating the portions 39 and 40 and a tab 48 identical to that of FIGS. 1 and 2 projects from the end of the pin to engage the center conductor of the stripline 18d. In this connector, the diameter of the pin 41d and the dimensions of the opening 38d and those previously given with respect to FIGS. 1 and 2.

Although the invention has been described herein with reference to specific embodiments, many modifications and variations therein will readily occur to those skilled in the art. Accordingly, all such variations and modifications are included within the intended scope of the invention as defined by the following claims.

I claim:

'1. A microwave connector comprising a member adapted to be connected to a microwave component having a circular cross-sectional configuration and to another microwave component having a rectangular cross-sectional configuration, means forming in the member an opening of circular cross-section of selected diameter at the end adjacent to the intended location of the component of circular cross-sectional configuration and an opening of circular cross-section having a smaller diameter at the end adjacent to the intended location of the component of rectangular cross-sectional configuration and connector pin means centrally supported within the opening and extending to opposite ends thereof, said pin means comprising a pin member of circular cross-section terminating in one end surface adjacent to the intended location of the component of circular cross-sectional configuration and terminating in the other end surface perpendicular to the axis of the pin member in a plane extending substantially through the junction of the selected diameter and smaller diameter circular openings and a thin tab member of rectangular cross-section projecting from one end of the pin member to the intended location of the component of rectangular cross-sectional configuration.

2. A microwave connector according to claim 1 wherein the tab member extending through the smaller diameter opening is narrower than the diameter of the pin member.

3. A microwave connector according to claim 1 including insulating ring means supporting the pin means in the member, and means forming a recess in the side of the insulating ring means adjacent to the opening in the member, the recess having a larger transverse dimension than the dimension of the opening.

4. A microwave connector according to claim 3 including further means forming a recess in the central portion of said insulating ring means and wherein the pin member includes a disk mounted therearound for positioning in the recess in the central portion of the insulating ring means to thereby prevent longitudinal displacement of the pin member.

5. A microwave connector comprising a member adapted to be connected to a microwave component having a circular cross-sectional configuration and to another microwave component having a rectangular crosssectional configuration, means forming in the member an opening of circular cross-section having a constant diameter situated between the intended position of the component of circular cross-sectional configuration and the intended position of the component of rectangular crosssectional configuration, and connector pin means centrally supported within the opening and extending to opposite ends thereof, said pin means comprising a pin member of circular cross-section extending halfway along the opening from the end adjacent to the intended location of the component of circular cross-sectional configuration and a thin tab member extending from the end of the pin member within the constant diameter opening to the intended location of the component of rectangular cross-section, the tab member being wider than the diameter of a pin member.

6. A microwave connector according to claim 5 wherein the end of the tab member within the constant diameter opening is received in a slot in the end of the pin member and is tapered to a width equal to the diameter of the pin member.

7. A microwave connector comprising a member adapted to be connected to a microwave component having a circular cross-sectional configuration and to another microwave component having a rectangular cross-sectional configuration, means forming in the member an opening of circular cross-section having a constant diameter situated between the intended position of the component of circular cross-sectional configuration and the intended position of the component of rectangular crosssectional configuration, and connector pin means centrally supported within the opening and extending to opposite ends thereof, said pin means comprising a pin member of circular cross-section extending into the opening from the end adjacent to the intended location of the component of circular cross-sectional configuration and a thin tab member extending from the end of the pin member within the constant diameter opening to the intended location of the component of rectangular cross-section, the tab member being Wider than the diameter of a pin member, and wherein the end of the pin member within the constant diameter opening is tapered.

8. A microwave connector according to claim 7 where in the tab member includes a projecting portion extending beyond the end of the constant diameter opening, the projecting portion having a narrower width than the remainder of the tab member.

References Cited UNITED STATES PATENTS 8/1965 Voelcker 333-97 8/1965 May 33384 

1. A MICROWAVE CONNECTOR COMPRISING A MEMBER ADAPTED TO BE CONNECTED TO A MICROWAVE COMPONENT HAVING A CIRCULAR CROSS-SECTIONAL CONFIGURATION AND TO ANOTHER MICROWAVE COMPONENT HAVING A RECTANGULAR CROSS-SECTIONAL CONFIGURATION, MAENS FORMING IN THE MEMBER AN OPENING OF CIRCULAR CROSS-SECTION OF SELECTED DIAMETER AT THE END ADJACENT TO THE INTENDED LOCATION OF THE COMPONENT OF CIRCULAR CROSS-SECTIONAL CONFIGURATION AND AN OPENING OF CIRCULAR CROSS-SECTION HAVING A SMALLER DIAMETER AT THE END ADJACENT TO THE INTENDED LOCATION OF THE COMPONENT OF RECTANGULAR CROSS-SECTIONAL CONFIGURATION AND CONNECTOR PIN MEANS CENTRALLY SUPPORTED WITHIN THE OPENING AND EXTENDING TO OPPOSITE ENDS THEREOF, SAID PIN MEANS COMPRISING A PIN MEMBER OF CIRCULAR CROSS-SECTION TER MINATING IN ONE END SURFACE ADJACENT TO THE INTENDED LOCATION OF THE COMPONENT OF CIRCULAR CROSS-SECTIONAL CONFIGURATION AND TERMINATING IN THE OTHER END SURFACE PERPENDICULAR TO THE AXIS OF THE PIN MEMBER IN A PLANE EXTENDING SUBSTANTIALLY THROUGH THE JUNCTION OF THE SELECTED DIAMETER AND SMALLER DIAMETER CIRCULAR OPENINGS AND A THIN TAB MEMBER OF RECTANGULAR CROSS-SECTION PROJECTING FROM ONE END OF THE PIN MEMBER TO THE INTENDED LOCATION OF THE COMPONENT OF RECTANGULAR CROSS-SECTIONAL CONFIGURATION. 